Birds known as Aves, are a group of endothermic vertebrates, characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, a strong yet lightweight skeleton. Birds range in size from the 5 cm bee hummingbird to the 2.75 m ostrich. They rank as the world's most numerically-successful class of tetrapods, with ten thousand living species, more than half of these being passerines, sometimes known as perching birds. Birds have wings which are less developed depending on the species. Wings, which evolved from forelimbs, gave birds the ability to fly, although further evolution has led to the loss of flight in flightless birds, including ratites and diverse endemic island species of birds; the digestive and respiratory systems of birds are uniquely adapted for flight. Some bird species of aquatic environments seabirds and some waterbirds, have further evolved for swimming; the fossil record demonstrates that birds are modern feathered dinosaurs, having evolved from earlier feathered dinosaurs within the theropod group, which are traditionally placed within the saurischian dinosaurs.
The closest living relatives of birds are the crocodilians. Primitive bird-like dinosaurs that lie outside class Aves proper, in the broader group Avialae, have been found dating back to the mid-Jurassic period, around 170 million years ago. Many of these early "stem-birds", such as Archaeopteryx, were not yet capable of powered flight, many retained primitive characteristics like toothy jaws in place of beaks, long bony tails. DNA-based evidence finds that birds diversified around the time of the Cretaceous–Palaeogene extinction event 66 million years ago, which killed off the pterosaurs and all the non-avian dinosaur lineages, but birds those in the southern continents, survived this event and migrated to other parts of the world while diversifying during periods of global cooling. This makes them the sole surviving dinosaurs according to cladistics; some birds corvids and parrots, are among the most intelligent animals. Many species annually migrate great distances. Birds are social, communicating with visual signals and bird songs, participating in such social behaviours as cooperative breeding and hunting and mobbing of predators.
The vast majority of bird species are monogamous for one breeding season at a time, sometimes for years, but for life. Other species have breeding systems that are polygynous or polyandrous. Birds produce offspring by laying eggs, they are laid in a nest and incubated by the parents. Most birds have an extended period of parental care after hatching; some birds, such as hens, lay eggs when not fertilised, though unfertilised eggs do not produce offspring. Many species of birds are economically important as food for human consumption and raw material in manufacturing, with domesticated and undomesticated birds being important sources of eggs and feathers. Songbirds and other species are popular as pets. Guano is harvested for use as a fertiliser. Birds prominently figure throughout human culture. About 120–130 species have become extinct due to human activity since the 17th century, hundreds more before then. Human activity threatens about 1,200 bird species with extinction, though efforts are underway to protect them.
Recreational birdwatching is an important part of the ecotourism industry. The first classification of birds was developed by Francis Willughby and John Ray in their 1676 volume Ornithologiae. Carl Linnaeus modified that work in 1758 to devise the taxonomic classification system in use. Birds are categorised as the biological class Aves in Linnaean taxonomy. Phylogenetic taxonomy places Aves in the dinosaur clade Theropoda. Aves and a sister group, the clade Crocodilia, contain the only living representatives of the reptile clade Archosauria. During the late 1990s, Aves was most defined phylogenetically as all descendants of the most recent common ancestor of modern birds and Archaeopteryx lithographica. However, an earlier definition proposed by Jacques Gauthier gained wide currency in the 21st century, is used by many scientists including adherents of the Phylocode system. Gauthier defined Aves to include only the crown group of the set of modern birds; this was done by excluding most groups known only from fossils, assigning them, instead, to the Avialae, in part to avoid the uncertainties about the placement of Archaeopteryx in relation to animals traditionally thought of as theropod dinosaurs.
Gauthier identified four different definitions for the same biological name "Aves", a problem. Gauthier proposed to reserve the term Aves only for the crown group consisting of the last common ancestor of all living birds and all of its descendants, which corresponds to meaning number 4 below, he assigned other names to the other groups. Aves can mean all archosaurs closer to birds than to crocodiles Aves can mean those advanced archosaurs with feathers Aves can mean those feathered dinosaurs that fly Aves can mean the last common ancestor of all the living birds and all of its descendants (a "c
Natalia Sergeevna Polevshchikova shortened to Natasha Poly, is a Russian model. Since 2004, Poly has appeared in prominent high-fashion advertisement campaigns, magazine covers and on runways. Poly established herself as one of the most "in-demand models" of the mid and late 2000's, with Vogue Paris declaring her as one of the top 30 models of the 2000s. Poly was born on July 12, 1985 in Perm, Russian SFSR, Soviet Union and began modeling locally in 2000, she was discovered in Perm by Mauro Palmentieri and invited to Moscow to participate in the Russian model search competition "New Model Today", where she took the second prize. She made her runway debut with Why Not Model Agency after walking for Emanuel Ungaro in 2004; the year would prove to be her breakout year. Since her breakout year in 2004, Poly has appeared in many advertisement campaigns, including Gucci, Versace, Calvin Klein Jeans, Dante Herró, Fendi, Louis Vuitton, Roberto Cavalli, Ralph Lauren, Marc Jacobs, Michael Kors, Dsquared2, Sonia Rykiel, Nine West, Proenza Schouler, H&M, Blumarine, Thierry Mugler, Kurt Geiger, Jil Sander, Nina Ricci, Isabel Marant, Neiman Marcus, L'Oréal Paris, Jimmy Choo, MaxMara, Alberta Ferretti, JOOP!, PHI, Juicy Couture, La Perla, FRAME Denim, Versace Sports Line, Emilio Pucci and Dolce & Gabbana.
Poly has walked the runway for designers such as Balenciaga, Alexander McQueen, Miu Miu, Prada and Victoria's Secret. Poly has been photographed by fashion photographers such as Helmut Newton, Steven Meisel and Marcus, Steven Klein, Mario Sorrenti, Mario Testino, David Sims and Vinoodh, Peter Lindbergh, Patrick Demarchelier, Nick Knight, Karl Lagerfeld, Annie Leibovitz, Craig McDean, Hans Feurer, Terry Richardson, Norman Jean Roy, Camilla Akrans, Alasdair McLellan, Ellen Von Unwerth, Emma Summerton, Josh Olins, Mikael Jansson, Daniel Jackson, Tom Munro, Willy Vanderperre, Michael Thompson and Iango, Sølve Sundsbø, Giampaolo Sgura, Richard Bush, Victor Demarchelier, Cuneyt Akeroglu among others. Three fashion magazines has dedicated their entire issue to her, a very rare feat for models; these are: MUSE Magazine and Vogue Espana. Poly has walked for the annual Victoria's Secret Fashion Show twice, in 2005 and 2006. In 2008 alone, she appeared in seven advertisement campaigns through the fall/winter 2008–09 season for Nina Ricci, Jil Sander, Balmain, H&M, Tse and Givenchy and opened numerous runway shows in the spring/summer 2009 season.
Poly has endorsed and appeared in advertisements for fragrances including Givenchy's Ange ou Demon, Gucci by Gucci Fragrance, Jimmy Choo Flash. Poly was one of the faces to headline one of the fourteen covers of V magazine's September 2008 issue; each cover featured a head shot of a famous model, either from the new crop of leading models or the supermodel era, it was lensed by duo Inez van Lamsweerde and Vinoodh Matadin. In July 2008, Russian Vogue dedicated the issue to Poly and in August 2008, March 2009 she appeared on the cover of the same magazine, she was touted by American Vogue in 2009 as one of the faces of the moment. She has appeared on the covers of Spanish, Portuguese, Korean, Chinese, German, Australian and French Vogue. Poly has appeared in editorials for Russian, Italian, Japanese, Spanish, Greek and American Vogue as well as covers for Numero, I-D Magazine, V, W, Interview, MUSE and Harper's Bazaar. Poly was placed 1st on Fashion Television's First Face countdown three times consecutively.
She was placed 7th, 4th and 5th. First Face. Vogue Paris declared her one of the top 30 models of the 2000s. Poly is featured in the 2011 Pirelli Calendar photographed by Karl Lagerfeld, she featured in the 2012 Pirelli Calendar photographed by Mario Sorrenti. In 2012, Poly signed a contract with L'Oreal Paris and is one of the Beauty Ambassadors for the brand. Poly was part of the Versace Spring/Summer 2016 Campaign, alongside Gigi Hadid and Raquel Zimmermann, shot by Steven Klein, she appeared in a commercial for Mercedes-Benz, captured by Jeff Mark, entitled'Obsession with an Icon’, Natasha fronted in a blue latex clad to the Mercedes-Benz SL car. She became the face for Kurt Geiger's Fall/Winter 2016 Campaign. In 2017, Poly became one of the front faces and muse in Olivier Rousteing's Balmain for the Spring/Summer and Fall/Winter 2017 Campaign. Poly returned for Dsquared2 in their campaign for F/W 17 co starring other models such as Joan Smalls and Sasha Pivovarova, she became David Koma's muse for Thierry Mugler Fall/Winter 2017 Campaign.
She is considered one of the "New Supers" by Models.com and has been featured on 56 different Vogue covers as of November 2017. Poly married Dutch businessman Peter Bakker on April 2011 in Saint-Tropez. On May 13, 2013 Poly gave birth to a daughter named Aleksandra Christina. In April 2019, she gave birth to a son named Adrian Grey Bakker. Among the best friends of Natasha are top model Eugenia Volodina and popular Russian musician DJ Smash. Natasha Poly on Instagram. Natasha Poly at Models.com. Women Management Portfolio
The temporal fossa is a shallow depression on the side of the skull bounded by the temporal lines and terminating below the level of the zygomatic arch. Medial: frontal bone, parietal bone, temporal bone, sphenoid bone. Lateral: Temporal fascia Anterior: Posterior surface of the frontal process of the zygomatic bone and the posterior surface of the zygomatic process of the frontal bone. Superior: Pair of temporal lines that arch across the skull from the zygomatic process of the frontal bone to the supramastoid crest of the temporal bone Inferior: Zygomatic arch laterally and by the infratemporal crest of the greater wing of the sphenoid medially. Osteology Temporal fossa, boundaries & contents Infratemporal fossa, boundaries & contents Muscles of mastication Maxillary artery Pterygoid venous plexus Mandibular nerve Temporomandibular Joint Temporalis muscle Deep temporal arteries Deep temporal nerves Superficial temporal artery Zygomaticotemporal nerve
The irregular bones are bones which, from their peculiar form, cannot be grouped as long, flat or sesamoid bones. Irregular bones serve various purposes in the body, such as protection of nervous tissue, affording multiple anchor points for skeletal muscle attachment, maintaining pharynx and trachea support, tongue attachment, they consist of cancellous tissue enclosed within a thin layer of compact bone. Irregular bones can be used for joining all parts of the spinal column together; the spine is the place in the human body. There are, in all, 33 irregular bones found here; the irregular bones are: the vertebrae, scapula, temporal, ethmoid, maxilla, palatine, inferior nasal concha, hyoid. This article incorporates text in the public domain from page 80 of the 20th edition of Gray's Anatomy Stedman's Online Medical Dictionary, 27th Edition
Tetrapods are four-limbed animals constituting the superclass Tetrapoda. It includes existing and extinct amphibians and mammals. Tetrapods evolved from a group of animals known as the Tetrapodomorpha which, in turn, evolved from ancient Sarcopterygii around 390 million years ago in the middle Devonian period; the first tetrapods appeared by the late Devonian, 367.5 million years ago. The change from a body plan for breathing and navigating in water to a body plan enabling the animal to move on land is one of the most profound evolutionary changes known; the first tetrapods were aquatic. Modern amphibians, which evolved from earlier groups, are semiaquatic. However, most tetrapod species today are amniotes, most of those are terrestrial tetrapods whose branch evolved from earlier tetrapods about 340 million years ago; the key innovation in amniotes over amphibians is laying of eggs on land or having further evolved to retain the fertilized egg within the mother. Amniote tetrapods drove most amphibian tetrapods to extinction.
One group of amniotes diverged into the reptiles, which includes lepidosaurs, crocodilians and extinct relatives. Amniotes include the tetrapods that further evolved for flight—such as birds from among the dinosaurs, bats from among the mammals; some tetrapods, such as the snakes, have lost some or all of their limbs through further speciation and evolution. Others, such as amphibians, returned to or aquatic lives, the first during the Carboniferous period. Tetrapods have numerous anatomical and physiological features that are distinct from their aquatic ancestors; these include the structure of the jaw and teeth for feeding on land, limb girdles and extremities for land locomotion, lungs for respiration in air, a heart for circulation, eyes and ears for seeing and hearing in air. Tetrapods can be defined in cladistics as the nearest common ancestor of all living amphibians and all living amniotes, along with all of the descendants of that ancestor; this is a node-based definition. The group so defined is crown tetrapods.
The term tetrapodomorph is used for the stem-based definition: any animal, more related to living amphibians, reptiles and mammals than to living dipnoi. The group so defined is known as the tetrapod total group. Stegocephalia is a larger group equivalent to some broader uses of the word tetrapod, used by scientists who prefer to reserve tetrapod for the crown group; such scientists use the term "stem-tetrapod" to refer to those tetrapod-like vertebrates that are not members of the crown group, including the tetrapodomorph fishes. The two subclades of crown tetrapods are Reptiliomorpha. Batrachomorphs are all animals sharing a more recent common ancestry with living amphibians than with living amniotes. Reptiliomorphs are all animals sharing a more recent common ancestry with living amniotes than with living amphibians. Tetrapoda includes four living classes: amphibians, reptiles and birds. Overall, the biodiversity of lissamphibians, as well as of tetrapods has grown exponentially over time. However, that diversification process was interrupted at least a few times by major biological crises, such as the Permian–Triassic extinction event, which at least affected amniotes.
The overall composition of biodiversity was driven by amphibians in the Palaeozoic, dominated by reptiles in the Mesozoic and expanded by the explosive growth of birds and mammals in the Cenozoic. As biodiversity has grown, so has the number of niches that tetrapods have occupied; the first tetrapods were aquatic and fed on fish. Today, the Earth supports a great diversity of tetrapods that live in many habitats and subsist on a variety of diets; the following table shows summary estimates for each tetrapod class from the IUCN Red List of Threatened Species, 2014.3, for the number of extant species that have been described in the literature, as well as the number of threatened species. The classification of tetrapods has a long history. Traditionally, tetrapods are divided into four classes based on gross anatomical and physiological traits. Snakes and other legless reptiles are considered tetrapods because they are sufficiently like other reptiles that have a full complement of limbs. Similar considerations apply to aquatic mammals.
Newer taxonomy is based on cladistics instead, giving a variable number of major "branches" of the tetrapod family tree. As is the case throughout evolutionary biology today, there is debate over how to properly classify the groups within Tetrapoda. Traditional biological classification sometimes fa
In biology, homology is the existence of shared ancestry between a pair of structures, or genes, in different taxa. A common example of homologous structures is the forelimbs of vertebrates, where the wings of bats, the arms of primates, the front flippers of whales and the forelegs of dogs and horses are all derived from the same ancestral tetrapod structure. Evolutionary biology explains homologous structures adapted to different purposes as the result of descent with modification from a common ancestor; the term was first applied to biology in a non-evolutionary context by the anatomist Richard Owen in 1843. Homology was explained by Charles Darwin's theory of evolution in 1859, but had been observed before this, from Aristotle onwards, it was explicitly analysed by Pierre Belon in 1555. In developmental biology, organs that developed in the embryo in the same manner and from similar origins, such as from matching primordia in successive segments of the same animal, are serially homologous.
Examples include the legs of a centipede, the maxillary palp and labial palp of an insect, the spinous processes of successive vertebrae in a vertebral column. Male and female reproductive organs are homologous if they develop from the same embryonic tissue, as do the ovaries and testicles of mammals including humans. Sequence homology between protein or DNA sequences is defined in terms of shared ancestry. Two segments of DNA can have shared ancestry because of either a speciation event or a duplication event. Homology among proteins or DNA is inferred from their sequence similarity. Significant similarity is strong evidence that two sequences are related by divergent evolution from a common ancestor. Alignments of multiple sequences are used to discover the homologous regions. Homology remains controversial in animal behaviour, but there is suggestive evidence that, for example, dominance hierarchies are homologous across the primates. Homology was noticed by Aristotle, was explicitly analysed by Pierre Belon in his 1555 Book of Birds, where he systematically compared the skeletons of birds and humans.
The pattern of similarity was interpreted as part of the static great chain of being through the mediaeval and early modern periods: it was not seen as implying evolutionary change. In the German Naturphilosophie tradition, homology was of special interest as demonstrating unity in nature. In 1790, Goethe stated his foliar theory in his essay "Metamorphosis of Plants", showing that flower part are derived from leaves; the serial homology of limbs was described late in the 18th century. The French zoologist Etienne Geoffroy Saint-Hilaire showed in 1818 in his theorie d'analogue that structures were shared between fishes, reptiles and mammals; when Geoffroy went further and sought homologies between Georges Cuvier's embranchements, such as vertebrates and molluscs, his claims triggered the 1830 Cuvier-Geoffroy debate. Geoffroy stated the principle of connections, namely that what is important is the relative position of different structures and their connections to each other; the Estonian embryologist Karl Ernst von Baer stated what are now called von Baer's laws in 1828, noting that related animals begin their development as similar embryos and diverge: thus, animals in the same family are more related and diverge than animals which are only in the same order and have fewer homologies.
Von Baer's theory recognises that each taxon has distinctive shared features, that embryonic development parallels the taxonomic hierarchy: not the same as recapitulation theory. The term "homology" was first used in biology by the anatomist Richard Owen in 1843 when studying the similarities of vertebrate fins and limbs, defining it as the "same organ in different animals under every variety of form and function", contrasting it with the matching term "analogy" which he used to describe different structures with the same function. Owen codified 3 main criteria for determining if features were homologous: position and composition. In 1859, Charles Darwin explained homologous structures as meaning that the organisms concerned shared a body plan from a common ancestor, that taxa were branches of a single tree of life; the word homology, coined in about 1656, is derived from the Greek ὁμόλογος homologos from ὁμός homos "same" and λόγος logos "relation". Biological structures or sequences in different taxa are homologous if they are derived from a common ancestor.
Homology thus implies divergent evolution. For example, many insects possess two pairs of flying wings. In beetles, the first pair of wings has evolved into a pair of hard wing covers, while in Dipteran flies the second pair of wings has evolved into small halteres used for balance; the forelimbs of ancestral vertebrates have evolved into the front flippers of whales, the wings of birds, the running forelegs of dogs and horses, the short forelegs of frogs and lizards, the grasping hands of primates including humans. The same major forearm bones are found in fossils of lobe-finned fish such as Eusthenopteron; the opposite of homologous organs are analogous organs which do similar jobs in two taxa that were not present in their most recent common ancestor but rather evolved separately. For example, the wings of insects and birds evolved independently in separated groups, converged functionally to support powered flight, so they are analogous; the wings of a sycamore maple seed and the wings of a bird are analogous but not homologous, as they develop from quite different structures.
A structure can be only analogous at another. Pterosaur and bat wings are analogous as wings
Edmontosaurus is a genus of hadrosaurid dinosaur. It contains two known species: Edmontosaurus annectens. Fossils of E. regalis have been found in rocks of western North America that date from the late Campanian stage of the Cretaceous Period 73 million years ago, while those of E. annectens were found in the same geographic region but in rocks dated to the end of the Maastrichtian stage of the Cretaceous, 66 million years ago. Edmontosaurus was one of the last non-avian dinosaurs, lived alongside dinosaurs like Triceratops, Tyrannosaurus and Pachycephalosaurus shortly before the Cretaceous–Paleogene extinction event. Edmontosaurus included some of the largest hadrosaurid species, measuring up to 12 metres long and weighing around 4.0 metric tons. Evidence does exist in the form of two fossilized specimens housed at the Museum of the Rockies for an greater maximum size of 15 m and weighing 9.07 metric tons for Edmontosaurus annectens. Several well-preserved specimens are known that include not only bones, but in some cases extensive skin impressions and possible gut contents.
It is classified as a genus of saurolophine hadrosaurid, a member of the group of hadrosaurids which lacked large, hollow crests, instead having smaller solid crests or fleshy combs. The first fossils named Edmontosaurus were discovered in southern Alberta, in the Horseshoe Canyon Formation; the type species, E. regalis, was named by Lawrence Lambe in 1917, although several other species that are now classified in Edmontosaurus were named earlier. The best known of these is E. annectens, named by Othniel Charles Marsh in 1892. Anatosaurus and Anatotitan are now regarded as synonyms of Edmontosaurus. Edmontosaurus was distributed across western North America; the distribution of Edmontosaurus fossils suggests that it preferred coastal plains. It was a herbivore that could move on four; because it is known from several bone beds, Edmontosaurus is thought to have lived in groups, may have been migratory as well. The wealth of fossils has allowed researchers to study its paleobiology in detail, including its brain, how it may have fed, its injuries and pathologies, such as evidence for tyrannosaur attacks on a few edmontosaur specimens.
Edmontosaurus has had a long and complicated history in paleontology, having spent decades with various species classified in other genera. Its taxonomic history intertwines at various points with the genera Agathaumas, Anatotitan, Hadrosaurus and Trachodon, references predating the 1980s use Anatosaurus, Thespesius, or Trachodon for edmontosaur fossils, depending on author and date. Although Edmontosaurus was only named in 1917, its oldest well-supported species was named in 1892 as a species of Claosaurus; the first well-supported species of Edmontosaurus was named in 1892 as Claosaurus annectens by Othniel Charles Marsh. This species is based on USNM 2414, a partial skull-roof and skeleton, with a second skull and skeleton, YPM 2182, designated the paratype. Both were collected in 1891 by John Bell Hatcher from the late Maastrichtian-age Upper Cretaceous Lance Formation of Niobrara County, Wyoming; this species has some historical footnotes attached: it is among the first dinosaurs to receive a skeletal restoration, is the first hadrosaurid so restored.
YPM 2182 was put on display in 1901, USNM 2414 in 1904. Because of the incomplete understanding of hadrosaurids at the time, following Marsh's death in 1897 Claosaurus annectens was variously classified as a species of Claosaurus, Thespesius or Trachodon. Opinions varied greatly. Hatcher's revision, published in 1902, was sweeping: he considered all hadrosaurid genera known as synonyms of Trachodon; this included Cionodon, Hadrosaurus, Ornithotarsus and Thespesius, as well as Claorhynchus and Polyonax, fragmentary genera now thought to be horned dinosaurs. Hatcher's work led to a brief consensus, until after 1910 new material from Canada and Montana showed a greater diversity of hadrosaurids than suspected. Charles W. Gilmore in 1915 reassessed hadrosaurids and recommended that Thespesius be reintroduced for hadrosaurids from the Lance Formation and rock units of equivalent age, that Trachodon, based on inadequate material, should be restricted to a hadrosaurid from the older Judith River Formation and its equivalents.
In regards to Claosaurus annectens, he recommended that it be considered the same as Thespesius occidentalis. His reinstatement of Thespesius for Lance-age hadrosaurids would have other consequences for the taxonomy of Edmontosaurus in the following decades. During this time frame, two additional important specimens of C. annectens were recovered. The first, the "Trachodon mummy", was discovered in 1908 by Charles Hazelius Sternberg and his sons in Lance Formation rocks near Lusk, Wyoming. Stern